147 research outputs found
Characterization of common marmoset (Callithrix jacchus) bone marrow-derived mesenchymal stem cells
Abstract: Mesenchymal stem cells (MSCs) could be useful for regenerative medicine because they can beharvested easily from the bone marrow of living donors and the cells can be differentiated into adipogenic, osteogenic, and chondrogenic lineages in vitro. To apply MSCs for the medical treatment of human diseases as regenerative medicine, detailed experimental characterization of the cells is required. Recently, a New World primate, the common marmoset (Callithrix jacchus), has been widely used as a new human disease model because of its ease of handling and breeding. Although common marmoset MSCs have been established and will be used in preclinical studies of regenerative medicine, the characteristics of these cells remain unclear. Aiming to characterize common marmoset MSCs further, we harvested common marmoset bone marrow-derived cells (cmBMDCs) from the femurs of newborn males. We revealed that the morphology of the cells was similar to common marmoset fibroblasts, and extracellular matrix components, such as gelatin and fibronectin, were effective for their proliferation and formation of colony-forming unit fibroblasts. Furthermore, we were able to differentiate cmBMDCs into adipocytes, osteocytes, and chondrocytes in vitro, and they expressed the MSCmarkers CD44, CD73, CD90, and CD105, but their expression decreased with increasing passage number. The data demonstrate that cmBMDCs exhibit characteristics of MSCs and thus it would be beneficial to use these cells in preclinical studies
Examining the assembly pathways and active microtubule mechanics underlying spindle self-organization
The bipolar organization of the microtubule-based mitotic spindle is
essential for the faithful segregation of chromosomes in cell division. Despite
our extensive knowledge of genes and proteins, the physical mechanism of how
the ensemble of microtubules can assemble into a proper bipolar shape remains
elusive. Here, we study the pathways of spindle self-organization using
cell-free Xenopus egg extracts and computer-based automated shape analysis. Our
microscopy assay allows us to simultaneously record the growth of hundreds of
spindles in the bulk cytoplasm and systematically analyze the shape of each
structure over the course of self-organization. We find that spindles that are
maturing into a bipolar shape take a route that is distinct from those ending
up with faulty structures, such as those of a tripolar shape. Moreover, matured
structures are highly stable with little occasions of transformation between
different shape phenotypes. Visualizing the movement of microtubules further
reveals a fraction of microtubules that assemble between extra poles and push
the poles apart, suggesting the presence of active extensile force that
prevents pole coalescence. Together, we propose that a proper control over the
magnitude and location of the extensile, pole-pushing force is crucial for
establishing spindle bipolarity while preventing multipolarity.Comment: 22 pages, 5 + 2 figure
Optical resolution via catalytic generation of chiral auxiliary
A new catalytic method for separating enantiomers of racemic compounds is proposed. Catalytic asymmetric addition of chiral trans-2-substituted cyclohexanols to imines provided diastereomeric mixtures of aminals, and the subsequent separation of the enantiomers by silicagel column chromatography and the hydrolysis of the aminals produced the alcohols in an optically active form
Striking Difference between Succinimidomethyl and Phthalimidomethyl Radicals in Conjugate Addition to Alkylidenemalonate Initiated by Dimethylzinc
We used dimethylzinc to develop a conjugate addition reaction of imidomethyl radicals to alkylidenemalonates using dimethylzinc, in which we observed a significant difference between succinimidomethyl and phthalimidomethyl radicals. This reaction provides new access to γ- aminobutyric acid derivatives, which often function as neurotransmitters
Desymmetrization of acid anhydride with asymmetric esterification catalyzed by chiral phosphoric acid
Asymmetric desymmetrization of σ-symmetric acid anhydrides was achieved with chiral phosphoric acid as a Brønsted acid catalyst. The key of success was finding of benzhydrol and 2,2-diphenylethanol as the nucleophiles of choice. The corresponding half esters were obtained in good yields with high selectivity
Acute inflammation at a mandibular solitary horizontal incompletely impacted molar
Acute inflammation is frequently seen in the elderly around incompletely impacted molars located apart from molars or premolars. To identify the factors causing acute inflammation in the solitary molars without second molars or without second and first molars, ages of patients and rates of acute inflammation in 75 horizontal incompletely impacted mandibular molars in contact or not in contact with molars in subjects 41 years old or older were studied using orthopantomographs. Acute inflammation was seen in nine third molars out of 48 third molars in contact with second molars (18.8%), whereas acute inflammation was seen in 11 molars out of 19 solitary molars without second molars or without first and second molars (57.9%) (p < 0.01). The mean age of 48 subjects with third molars in contact with the second molar was 50.42 ± 7.62 years, and the mean age of 19 subjects with isolated molars was 65.16 ± 10.41 years (p < 0.0001). These indicate that a solitary horizontal incompletely impacted molar leads more frequently to acute inflammation along with aging due to possible bone resorption resulting from teeth loss
Comparison of antioxidative effects between radon and thoron inhalation in mouse organs
Radon therapy has been traditionally performed globally for oxidative stress-related diseases. Many researchers have studied the beneficial effects of radon exposure in living organisms. However, the effects of thoron, a radioisotope of radon, have not been fully examined. In this study, we aimed to compare the biological effects of radon and thoron inhalation on mouse organs with a focus on oxidative stress. Male BALB/c mice were randomly divided into 15 groups: sham inhalation, radon inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3, and thoron inhalation at a dose of 500 Bq/m3 or 2000 Bq/m3 were carried out. Immediately after inhalation, mouse tissues were excised for biochemical assays. The results showed a significant increase in superoxide dismutase and total glutathione, and a significant decrease in lipid peroxide following thoron inhalation under several conditions. Additionally, similar effects were observed for different doses and inhalation times between radon and thoron. Our results suggest that thoron inhalation also exerts antioxidative effects against oxidative stress in organs. However, the inhalation conditions should be carefully analyzed because of the differences in physical characteristics between radon and thoron
Eukaryotic Components Remodeled Chloroplast Nucleoid Organization during the Green Plant Evolution.
Chloroplast (cp) DNA is thought to originate from the ancestral endosymbiont genome and is compacted to form nucleoprotein complexes, cp nucleoids. The structure of cp nucleoids is ubiquitously observed in diverse plants from unicellular algae to flowering plants and is believed to be a multifunctional platform for various processes, including cpDNA replication, repair/recombination, transcription, and inheritance. Despite its fundamental functions, the protein composition for cp nucleoids in flowering plants was suggested to be divergent from those of bacteria and algae, but the evolutionary process remains elusive. In this research, we aimed to reveal the evolutionary history of cp nucleoid organization by analyzing the key organisms representing the three evolutionary stages of eukaryotic phototrophs: the chlorophyte alga Chlamydomonas reinhardtii , the charophyte alga Klebsormidium flaccidum , and the most basal land plant Marchantia polymorpha . To clarify the core cp nucleoid proteins in C. reinhardtii , we performed an LC-MS/MS analysis using highly purified cp nucleoid fractions and identified a novel SAP domain-containing protein with a eukaryotic origin as a constitutive core component. Then, homologous genes for cp nucleoid proteins were searched for in C. reinhardtii , K. flaccidum , and M. polymorpha using the genome databases, and their intracellular localizations and DNA binding activities were investigated by cell biological/biochemical analyses. Based on these results, we propose a model that recurrent modification of cp nucleoid organization by eukaryotic factors originally related to chromatin organization might have been the driving force for the diversification of cp nucleoids since the early stage of green plant evolution
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